The proposal should significantly contribute to a better understanding of some of the biological mechanisms by which a neurological trauma produces retrograde amnesia. Experiments are proposed to investigate the effects of "amnesic" dose levels of Metrazol on levels of biogenic amines in the whole brain various intervals after training and drug administration. This will provide information about the level of these amines during the critical period of memory storage. Electrophysiological correlates of the training and drug treatment will be used to assess whether a predictive relationship exists between some parameters of EEG and subsequent retention performance, and if appropriate they will be considered with the biochemical results. Biogenic amine depletors and precursors will be used to test the hypothesis that biogenic amines play an important role during a critical period of memory storage and that a possible mechanism by which Metrazol produces amnesia is by altering these amine levels.